02-6630. Airworthiness Directives; Bombardier Model DHC-8-100, -200, and -300 Series Airplanes

AGENCY:

Federal Aviation Administration, DOT.

ACTION:

Notice of proposed rulemaking (NPRM).

SUMMARY:

This document proposes the adoption of a new airworthiness directive (AD) that is applicable to certain Bombardier Model DHC-8-100, -200, and -300 series airplanes. This proposal would require various modifications of the airstair (main passenger) door. This action is necessary to prevent failure of the airstair door to open after a landing, which could result in a blocked escape route during an emergency evacuation. This action is intended to address the identified unsafe condition.

DATES:

Comments must be received by April 19, 2002.

ADDRESSES:

Submit comments in triplicate to the Federal Aviation Administration (FAA), Transport Airplane Directorate, ANM-114, Attention: Rules Docket No. 2000-NM-307-AD, 1601 Lind Avenue, SW., Renton, Washington 98055-4056. Comments may be inspected at this location between 9:00 a.m. and 3:00 p.m., Monday through Friday, except Federal holidays. Comments may be submitted via fax to [phone]. Comments may also be sent via the Internet using the following address: [e-mail]. Comments sent via fax or the Internet must contain “Docket No. 2000-NM-307-AD” in the subject line and need not be submitted in triplicate. Comments sent via the Internet as attached electronic files must be formatted in Microsoft Word 97 for Windows or ASCII text.

The service information referenced in the proposed rule may be obtained from Bombardier, Inc., Bombardier Regional Aircraft Division, 123 Garratt Boulevard, Downsview, Ontario M3K 1Y5, Canada. This information may be examined at the FAA, Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton, Washington; or at the FAA, New York Aircraft Certification Office, 10 Fifth Street, Third Floor, Valley Stream, New York.

FOR FURTHER INFORMATION CONTACT:

Dan Parrillo, Aerospace Engineer, Systems and Flight Test Branch, ANE-172, FAA, New York Aircraft Certification Office, 10 Fifth Street, Third Floor, Valley Stream, New York 11581; telephone [phone]; fax [phone].

SUPPLEMENTARY INFORMATION:

Comments Invited

Interested persons are invited to participate in the making of the proposed rule by submitting such written data, views, or arguments as they may desire. Communications shall identify the Rules Docket number and be submitted in triplicate to the address specified above. All communications received on or before the closing date for comments, specified above, will be considered before taking action on the proposed rule. The proposals contained in this action may be changed in light of the comments received.

Submit comments using the following format:

• Organize comments issue-by-issue. For example, discuss a request to change the compliance time and a request to change the service bulletin reference as two separate issues.
• For each issue, state what specific change to the proposed AD is being requested.
• Include justification (e.g., reasons or data) for each request.

Comments are specifically invited on the overall regulatory, economic, environmental, and energy aspects of the proposed rule. All comments submitted will be available, both before and after the closing date for comments, in the Rules Docket for examination by interested persons. A report summarizing each FAA-public contact concerned with the substance of this proposal will be filed in the Rules Docket.

Commenters wishing the FAA to acknowledge receipt of their comments submitted in response to this action must submit a self-addressed, stamped postcard on which the following statement is made: “Comments to Docket 2000-NM-307-AD.” The postcard will be date-stamped and returned to the commenter.

Availability of NPRMs

Any person may obtain a copy of this NPRM by submitting a request to the FAA, Transport Airplane Directorate, ANM-114, Attention: Rules Docket 2000-NM-307-AD, 1601 Lind Avenue, SW., Renton, Washington 98055-4056.

Discussion

Transport Canada Civil Aviation (TCCA), which is the airworthiness authority for Canada, notified the FAA that an unsafe condition may exist on certain Bombardier Model DHC-8-100, -200, and -300 series airplanes. TCCA has received numerous reports of malfunctioning airstair (main passenger) doors on affected airplanes. During these malfunctions, crewmembers had difficulty opening or closing the door, or were completely unable to open the door from inside or outside. The airstair door is a “Type I” exit, which is essential for evacuation during an emergency. Causes of a failed airstair door include a malfunctioning inflation valve used for the door seal, bending of the gas springs (gas struts), and jamming and/or breaking of the door balance cable. Failure of the airstair door to open after a landing, if not corrected, could result in a blocked escape route during an emergency evacuation.

Explanation of Relevant Service Information

Bombardier has issued the service bulletins described in the following table:

Procedures for—	Are described in Service Bulletin—	Revision level—	Dated—
Replacing the inflation valve with a new valve of an improved design.	8-52-46	Original	September 30, 1998.
Reworking the airstair door cable balance assembly	8-52-38	Original ‘A’	October 10, 1995. September 19, 1997.
Modifying the cable guard system by replacing the upper cable guards with new, improved cable guards	8-52-57	Original ‘A’ ‘B’	February 23, 2000. July 28, 2000. November 14, 2000.
Modifying the airstair balance system by manufacturing and installing a support bracket assembly	8-52-56	‘C’ ‘D’ ‘E’ ‘F’ ‘G’	March 10, 2000. May 18, 2000. July 20, 2000. August 29, 2000. November 7, 2000.
Replacing the airstair door gas springs with new gas springs	8-52-59	Original ‘A’	September 18, 2000. January 3, 2001.

Accomplishment of the actions specified in the service bulletins is intended to adequately address the identified unsafe condition. TCCA classified Service Bulletins 8-52-46, 8-52-38, and 8-52-57 as mandatory; mandated accomplishment of either Service Bulletin 8-52-56 or 8-52-59 (and allowed accomplishment of both); and issued Canadian airworthiness directive CF-2000-19R1, dated January 22, 2001, to ensure the continued airworthiness of these airplanes in Canada.

FAA's Conclusions

These airplane models are manufactured in Canada and are type certificated for operation in the United States under the provisions of section 21.29 of the Federal Aviation Regulations (14 CFR 21.29) and the applicable bilateral airworthiness agreement. Pursuant to this bilateral airworthiness agreement, TCCA has kept the FAA informed of the situation described above. The FAA has examined the findings of TCCA, reviewed all available information, and determined that AD action is necessary for products of this type design that are certificated for operation in the United States.

Explanation of Requirements of Proposed Rule

Since an unsafe condition has been identified that is likely to exist or develop on other airplanes of the same type design registered in the United States, the proposed AD would require accomplishment of the actions specified in the service bulletins described previously.

Cost Impact

The FAA provides the following cost estimates for the actions specified by this proposed AD:

Action per Service Bulletin	Workhours per airplane	Labor rate per hour	Parts cost per airplane	Number of U.S. airplanes affected	Per-airplane cost	Fleet cost
8-52-46	3	$60	$297	194	$477	$92,538
8-52-38	4	60	1,930	130	2,170	282,100
8-52-57	1	60	0	194	60	11,640
8-52-56	4	60	0	194	240	46,560
8-52-59	3	60	0	194	180	34,920

The cost impact figures discussed above are based on assumptions that no operator has yet accomplished any of the proposed requirements of this AD action, and that no operator would accomplish those actions in the future if this proposed AD were not adopted. The cost impact figures discussed in AD rulemaking actions represent only the time necessary to perform the specific actions actually required by the AD. These figures typically do not include incidental costs, such as the time required to gain access and close up, planning time, or time necessitated by other administrative actions.

Regulatory Impact

The regulations proposed herein would not have a substantial direct effect on the States, on the relationship between the national Government and the States, or on the distribution of power and responsibilities among the various levels of government. Therefore, it is determined that this proposal would not have federalism implications under Executive Order 13132.

For the reasons discussed above, I certify that this proposed regulation (1) is not a “significant regulatory action” under Executive Order 12866; (2) is not a “significant rule” under the DOT Regulatory Policies and Procedures (44 FR 11034, February 26, 1979); and (3) if promulgated, will not have a significant economic impact, positive or negative, on a substantial number of small entities under the criteria of the Regulatory Flexibility Act. A copy of the draft regulatory evaluation prepared for this action is contained in the Rules Docket. A copy of it may be obtained by contacting the Rules Docket at the location provided under the caption ADDRESSES.

List of Subjects in 14 CFR Part 39

• Air transportation
• Aircraft
• Aviation safety
• Safety

The Proposed Amendment

Accordingly, pursuant to the authority delegated to me by the Administrator, the Federal Aviation Administration proposes to amend part 39 of the Federal Aviation Regulations (14 CFR part 39) as follows:

PART 39—AIRWORTHINESS DIRECTIVES

1. The authority citation for part 39 continues to read as follows:

Authority: 49 U.S.C. 106(g), 40113, 44701.

§ 39.13

[Amended]

2. Section 39.13 is amended by adding the following new airworthiness directive:

Bombardier, Inc. (Formerly de Havilland, Inc.): Docket 2000-NM-307-AD.

Applicability: Model DHC-8-100, -200, and -300 series airplanes; certificated in any category; serial numbers 003 through 550 inclusive.

Note 1:

This AD applies to each airplane identified in the preceding applicability provision, regardless of whether it has been modified, altered, or repaired in the area subject to the requirements of this AD. For airplanes that have been modified, altered, or repaired so that the performance of the requirements of this AD is affected, the owner/operator must request approval for an alternative method of compliance in accordance with paragraph (b) of this AD. The request should include an assessment of the effect of the modification, alteration, or repair on the unsafe condition addressed by this AD; and, if the unsafe condition has not been eliminated, the request should include specific proposed actions to address it.

Compliance: Required as indicated, unless accomplished previously.

To prevent failure of the airstair door to open after a landing, which could result in a blocked escape route during an emergency evacuation, accomplish the following:

Modifications

(a) Modify the airplane as specified by the following table:

Table—Modification Requirements

For Model—	Modify the airstair door by—	Within—	In accordance with the Accomplishment Instructions of Bombardier Service Bulletin—
(1) DHC-8-102, −103, −106, −201, 202, 301, −311, and −315 series airplanes; serial numbers 003 through 522 inclusive	Replacing the inflation valve with a new valve of an improved design (Modsum 8Q100185)	6 months after the effective date of this AD	8-52-46, dated September 30, 1998.
(2) DHC-8-102, −103, −106, −301, −311, and −315 series airplanes; serial numbers 003 through 400 inclusive	Reworking the airstair door cable balance assembly (Modsum 8/2205)	6 months after the effective date of this AD	8-52-38, dated October 10, 1995; or 8-52-38, Revision ‘A,’ dated September 19, 1997.
(3) DHC-8-102, −103, −106, −201, −202, −301, 311, and −315 series airplanes; serial numbers 003 through 550 inclusive	Replacing the upper cable guards on the airstair door with new, improved cable guards (Modsum 8Q101093)	6 months after the effective date of this AD, but after the modification required by paragraph (a)(2) of this AD	8-52-57, dated February 23, 2000; or 8-52-58, Revision ‘A,’ dated July 28, 2000; or 8-52-57, Revision ‘B,’ dated November 14, 2000.
(4) DHC-8-102, 103, 106, 201, 202, 301, 311, and 315 series airplanes; serial numbers 003 through 550 inclusive	(i) Manufacturing and installing a support bracket assembly (Modsum 8Q101086); and/or	6 months after the effective date of this AD	8-52-56, Revision ‘C,’ dated March 10, 2000; or 8-52-56, Revision ‘D,’ dated May 18, 2000; or 8-52-56, Revision ‘E,’ dated July 20, 2000; or 8-52-56, Revision ‘F,’ dated August 29, 2000; or 8-52-56, Revision ‘G,’ dated November 7, 2000.
	(ii) Replacing the airstair door gas springs with new gas springs (Modsum 8Q101074)	6 months after the effective date of this AD	8-52-59; dated September 18, 2000; or 8-52-59; Revision ‘A,’ dated January 3, 2001.

Note 2:

Modsum 8Q101093 (paragraph (a)(3) of this AD) cannot be accomplished before Modification 8/2205 (paragraph (a)(2) of this AD), because Modsum 8Q101093 introduces a redesigned cable guard that replaces a cable guard that is part of Modification 8/2205.

Note 3:

Modification as specified by either paragraph (a)(4)(i) or (a)(4)(ii)—or both—of this AD is acceptable for compliance with the requirements of paragraph (a)(4) of this AD.

Alternative Methods of Compliance

(b) An alternative method of compliance or adjustment of the compliance time that provides an acceptable level of safety may be used if approved by the Manager, New York Aircraft Certification Office (ACO), FAA. Operators shall submit their requests through an appropriate FAA Principal Maintenance Inspector, who may add comments and then send it to the Manager, New York ACO.

Note 4:

Information concerning the existence of approved alternative methods of compliance with this AD, if any, may be obtained from the New York ACO.

Special Flight Permits

(c) Special flight permits may be issued in accordance with sections 21.197 and 21.199 of the Federal Aviation Regulations (14 CFR 21.197 and 21.199) to operate the airplane to a location where the requirements of this AD can be accomplished.

Note 5:

The subject of this AD is addressed in Canadian airworthiness directive CF-2000-19R1, dated January 22, 2001.

Issued in Renton, Washington, on March 13, 2002.

Ali Bahrami,

Acting Manager, Transport Airplane Directorate, Aircraft Certification Service.